The present invention relates to a process for producing internal olefin sulfonates, being light-colored and substantially free from unreacted olefins, from a straight-chain internal olefin having from 10 to 22 carbon atoms.
It is well known that an olefin sulfonate, which can be used as an active component for detergents and the like, is obtainable through the steps of sulfonating an olefin with gaseous SO.sub.3, neutralizing the resulting sulfonation product, and thereafter hydrolyzing the same. In this case, as the starting material olefin there is commonly utilized vinylidene type olefin or alpha olefin, but an internal olefin is scarcely utilized therefor. In particular, this is because the internal olefin, which has a low reactivity to gaseous SO.sub.3 as compared with vinylidene type olefin or alpha olefin, can produce only a sulfonation product being deteriorated in color tone and moreover containing a large quantity of unreacted olefin under the conventional sulfonation conditions. As a matter of course, the quantity of unreacted olefin contained in the sulfonation product can be reduced to a certain extent by employing relatively severe sulfonation conditions, but in this case the sulfonation product is colored more conspicuously.